EBULLIOMETRIC DETERMINATION OF THE INFINITE DILUTION ACTIVITY COEFFICIENT' IDAC

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EBULLIOMETRIC DETERMINATION OF THE INFINITE
DILUTION ACTIVITY COEFFICIENT' (IDAC)

• TAs Bhavin Mehta
• Abhishek Maheshwari
• Staff V. P. Jadiyar
• Shaunak Dey

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AIM

• To determine the value of the "Infinite Dilution
  Activity Coefficient" (IDAC) of a binary at 1 atm
  pressure using differential ebulliometry and the
  limiting slope method.
• To estimate the parameters in the activity
  coefficients correlations such as Van Laar/Wilson.

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Infinite Dilution Activity Coefficient (IDAC)

• Maximum deviation from ideality occurs at
  infinite dilution.
• Indicator of the degree of the non-ideality of
  the solution.
• Phase equilibrium calculation can be performed
  using IDAC.
• Parameters of activity coefficient model can be
  determined.

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Theory of IDAC
IDAC of ith species can be given as
The following general relationship of the partial
derivatives exists for the variables T,P and x1.
Combining the two eqs, we get
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Ebulliometer

• It is a device which is used for precise and
  simultaneous measurement of both, the bubble
  point of a liquid and the dew point of the vapour

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Procedure

• Three ebulliometers are connected to a manifold
  and a common pressure system.
• Pure solution is charged to one of the
  ebulliometers while rest are with very dilute
  solutions in range of 0 5 mol percent.
• Set the pressure to atmospheric and switch ON
  heating supply.to each ebulliometer.
• After temp gets steady, count the avg drop rate
  of condensation of vapor per min and record it
  against temperature.
• Alter heat input by a very small amount and
  ensure if there any temp change occurs and also
  measure the drop rate as before.
• For each ebulliometer obtain at least 3 4 sets
  of temperature and drop rate (drop rate should
  not exceed 100/min) measurement.

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Calculations

• Plot T Vs Drop rate for each dilute solution
  separately. Extrapolate it to zero drop rate to
  get the bubble point temp of solution.
• Plot T vs x1 to find the slope of the best
  straight line. Calculate IDAC for 1st component
  using this slope.
• Repeat the above for other dilute (complementary
  experiment carried by other group).
• Check for ve or ve deviation from Raoults law.
• Determine Van Laar or Wilsons parameters and
  compare with literature data, if available.

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Additional Information

• TAs
• Abhishek Maheshwari abhishek.maheshwari_at_iitb.ac.
  in
• Bhavin Mehta bhavinmehta_at_iitb.ac.in
• Lab Manual is available on departmental website.
• http//www.che.iitb.ac.in/courses/uglab/uglabs.h
  tml
• References
• Introduction to Chemical Engineering
  Thermodynamics, J.M. Smith, H. C. Van Ness and M.
  M. Abott

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Thank you